【摘要】 用PVT法制备了6H-SiC。用光学显微镜观察了晶体生长面的原生形貌。讨论了6H-SiC中蜷线的形状及其形成机理。蜷线起源于螺旋位错,它们的形状则决定于这些位错的符号与相对位置。在(0001)Si面上,蜷线表现为圆形螺旋,而在(0001)C面上则表现为六角形螺旋。通常情况下,蜷线的极点没有任何包裹物。然而在某些情况下,蜷线的极点会出现包裹物,如夹杂、微管、孔洞或者负晶等。当(0001)Si面作为生长面时,6H-SiC单晶的生长机制符合螺旋位错模型(BCF理论模型)。更多还原

【Abstract】 6H-SiC single crystals were fabricated by using PVT technique.The morphology of as-grown crystal surface was investigated by optical microscopy.The formation mechanism and shapes of helices in 6H-SiC were discussed.The helices come of screw dislocations.And their shapes are determined by the signs and relative positions of screw dislocations of which they come.On the(0001)Si surface,helices show their shapes as circular spirals;those,however,on the(0001)C surface present as hexagonal spirals.In most cases,there is nothing in the center of helices.In some case,however,inclusions,micropipes,voids or negative crystals were found in the centers of them.The growth mechanism of 6H-SiC single crystal is accordant to the screw dislocation model(BCF theory model)with(0001)Si surface as the growth-surface.更多还原